He H.,Bohai Research Institute of Drilling and Exploration | Zhang H.,Bohai Research Institute of Drilling and Exploration | Liu X.,Bohai Research Institute of Drilling and Exploration | Liu Y.,Bohai Research Institute of Drilling and Exploration | And 2 more authors.Drilling Fluid and Completion Fluid | Year: 2014

A bi-lateral well was drilled in Halfaya Oilfield in Iraq. Acid stimulation was conducted after the completion of the first lateral, the main hole. Acid stimulation resulted in plenty of fractures and openings downhole, and the formations affected lost their pressure bearing capacity. The second lateral of the well, since connected with the first one, necessitated mud loss control with pressure-bearing LCM for successful drilling. Based on the understanding of mud loss characteristics, a compound hydratable swelling lost circulation material (LCM), BZ-STA, and an LCM used for mud loss control with pressure-bearing LCM, BZ-PRC, were developed. These two LCMs can effectively seal the 4-5 mm and 1-2 mm openings, respectively. These two LCMs, together with other conventional LCM, have been used to control mud losses after acid stimulation in three wells, in which the mud density was 1.23 g/cm3, and flow rate was 0.9 m3/min while controlling mud losses. The job was successful. Compared with conventional LCM, these new LCMs have better adaptability and higher rate of success.